The Callaway Energy Center reported the high chemical levels to the federal Nuclear Regulatory Commission (NRC). Victor Dricks with the NRC said the chemical concentrations in the water exceed EPA drinking water limits. Dricks said the contaminated water on plant grounds does not pose a threat to off-site water sources, people off site or workers onsite.

The groundwater contaminated with radioactive tritium and Cobalt-60, both byproducts of a nuclear reaction, were found in a well into which several pipes empty. After getting results from a July 25 test, the Associated Press reported, the plant stopped the water flow from those pipes. Dricks said Monday that the plant is investigating the source of the leak.

A number of nuclear plants around the country have also found tritium leaks on plant property and Dricks said the industry launched an aggressive monitoring system.

"The industry has undertaken a monitoring program to search for any indication of unplanned releases of tritium and as part of that program they have dug sampling wells both on the plant property and off the plant property so they can detect any releases," Dricks said. "These releases were found on the plant's property. They don't pose danger to people living near the plant or to the workers at the plant."

The NRC as the federal safety regulator has resident safety inspectors who work at the plant each day. Dricks said the inspectors are monitoring the plant's response to the event. The inspectors will conduct their own review of the response and situation, which the NRC will publish the results of in its quarterly inspection report.

Megan Favignano can be reached at (573) 826-2417 or at megan@fultonsun.com.